My Grinder Lied!

In February 2016, we published an article entitled” My Coffee Pot Lied.” It has become one of our most popular blog posts. In that article, we pointed out that the cup markings on coffee pots are not 8-ounce cups but may be 5-, 5.5- or 6-ounce cups depending on where the coffee brewer was manufactured.

We were recently looking at coffee grinders and came across this statement:

“For the richest coffee flavor, we suggest using one rounded tablespoon of ground coffee for every 5 ounces of water. The measurement markings in the grinder bowl indicate reference measurements. Fill beans to the marking level indicated by number of cups desired. For example, when making automatic drip coffee, if you fill the bowl with beans to the maximum 18 cup marking, you will have enough ground coffee for 18 cups”

There are problems with this statement. However, we don’t blame the grinder company. They are dealing with the reality that at 6 a.m. most consumers want a simple way to grind their coffee and cup markings are an easy solution.

The first problem is that tablespoons are volume measurements. However, not all coffee beans have the same density, so using volume measurements is inaccurate. Coffee grounds should be measured by weight. A rounded tablespoon of coffee might weigh 10 grams or 12 grams depending on the grind and the density. At 6 a.m. you may not care, but later in the day it makes a difference.

Cup markings on the side of the grinder receiver are also volume measurements and have the same problem as tablespoon measurements.

Another problem is that the statement assumes that the cup markings on your brewer indicate the same cup volume as the markings on your grinder. If you buy an American grinder the cup makings will probably be 6 ounces, but if your coffee brewer is Japanese the cup markings will be 5 ounces. If you use the above directions for an American grinder for 18 cups, you will grind 90 grams of ground coffee for 108 fluid ounces of water. But if you are using a Japanese brewer, you will only have 90 fluid ounces of water for 12 cups, so your coffee is going to be too strong.

If you want an accurate brew you need to use a scale. Food scales are cheap and will work. A good starting point for brewing coffee is to use 1 gram of coffee for each 18 grams of water. This is equal to about 10.57 grams of coffee for each 6 fluid ounces of water.

E ai kakou (Bon appetit)

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